Gunmen shot dead four members of a French family on Monday, including at least two children, and badly wounded the father in south-west Mauritania, the French embassy in Nouakchott said.
The attack happened at Aleg, 250km east of the capital, a security source said, adding that the gunmen were unidentified.
A correspondent for the daily Nouakchott Info who went to the scene said three men in a Mercedes car had carried out the attack, apparently with robbery as the motive.
A security source said three people were arrested late on Monday in Aleg in connection with the shooting.
Police said a vehicle matching the description had been found in Aleg and officers were searching the area.
The attack happened as the family was preparing to have a picnic lunch by the side of the road, they said.
An embassy official said the attack targeted ”five French people, a family”.
”There are four dead, including at least two children. The father was seriously wounded,” the official said.
”He has just been taken to the hospital at Aleg where he is receiving treatment.”
The father would be brought to Nouakchott as soon as possible, the official said, adding that the four bodies were also at the Aleg hospital.
None of the sources could say if the victims were tourists or residents in the former French colony in north-west Africa.
In Paris, French President Nicolas Sarkozy said: ”For the moment I can only confirm this tragic news and offer my condolences to the relatives.”
Speaking to journalists during a visit to a Paris hospital, Sarkozy said he would shortly be telephoning his Mauritanian counterpart, Sidi Ould Cheikh Abdallahi.
Although anyone venturing outside the capital is advised to travel in convoys of at least two vehicles, attacks of this kind in the Aleg region, southern Mauritania, are very rare.
The roads in the north-east desert region of the country, the border region with Mali, where Tuaregs and Islamists groups are active, are considered less safe. – Sapa-AFP